There are a number of known prior art devices for sorting particular objects or parts having a particular, preselected characteristic from a generalized stream of parts or for diverting selected segments of a flowing stream of fluid or granular matter from the main body of flow. Both of these tasks can employ the same apparatus and will hereinafter be considered collectively. Typically, these automatic sorting machines divert the parts possessing the particular characteristic so that they travel along a secondary path divergent from the primary path along which the generalized stream of parts travels. Most typically, the devices operate to sort out defective (too large, too small, irregular, etc.) parts as part of general quality control operations. In many cases, known types of optical-electronic sensors are used to identify those parts having the characteristic. When a part is detected that has a flaw or other characteristic, a signal is sent a mechanical means downstream of the sensor. Actuation of the mechanical device causes the defective part to be diverted or rejected from the generalized stream of perfect parts.
Examples of such mechanical sorting devices include U.S. Pat. Nos: 2,675,917; 3,052,351; 3,874,653; 4,314,645; and 4,813,205. Such prior art devices rely on magnetism, pneumatics, gravity, mechanical separators, etc., to sort and separate the objects which may include documents, produce, manufactured parts, etc. For example, U.S. Pat. No. 4,314,645 discloses a system in which a deflector 24 is moved by a cylinder 26 from a first to a second position so as to redirect the path of falling items. The deflector is in the form of a pusher plate which is reciprocated back and forth upon the end of a piston rod which moves in and out of a compressed air actuated cylinder. Thus, when the piston is actuated, the pusher plate mechanically pushes the defective part out of the parts stream and into another direction. Another type of device is disclosed in U.S. Pat. No. 4,813,205 which includes a deflector 43 coupled to a cylinder 46. The deflector 43 is in the form of curved deflector plate mechanically coupled to a piston rod. The deflector plate selectively opens and closes a gravity chute so that objects may either pass therethrough or be deflected into another path of travel. In some cases, these patented devices can also be used or modified to divert a portion of a passing stream of non-fungible material such as grain.
Such prior art sorting devices suffer from a number of problems. Many of them are mechanically very complex and tend to be subject to frequent failure and breakdown. Others frequently jam and call for considerable operator vigilance, a highly undesirable trait in an automated system. Others are simply unreliable in function and do not reliably divert the identified part on a regular basis.
Accordingly, there is a need for a simple diverter device which is inexpensive and easy to manufacture, which is not subject to mechanical breakdown or jamming, and which reliably and repeatedly diverts selected portions or defective items from a generalized flow of material.